Lubrication of tools



Patented Feb. 16, 1932 UNITED STATES ERNEST PENBERTHY, OF DETROIT, MICHIGAN, ASSIGNOB TO CHICAGO PNEUMATIC PATENT OFFICE TOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY LUBRICATION OF TOOLS Application fled February 4, 1925. Serial R'o. 6,819.

This invention relates to the lubrication of tools having a reciprocating member. While it possesses features of general utility and application to tools of this general charactor, it is particularly designed and intended for use with fluid pressure tools of the portable type which are commonly operated in all sorts of positions and which by reason of the rapidity of movement of the working parts require adequate and constant lubrication when in operation. More particularly the invention relates to percussive tools of the fluid pressure type utilizing a two diameter piston of which one pressure area is not vented at any time to atmosphere.

Among the objects of the invention are to provide in a tool of the class described a large reservoir for lubricant without increasing the size of the tool, to efiect automatically the feeding of lubricant from the reservoir when the tool is in operation regardless of the position of the tool, to prevent the feeding of lubricant when the tool is not in operation, and in general to improve the lubrication of tools and machines of the character described.

In order to illustrate the invention typical embodiments thereof are shown in the accompanying drawings, in which Fig. 1 is a vertical longitudinal sectional view substantially on theline 1-1 of Fig. 2 of a fluid pressure drill of the valveless type.

Fig. 2 is a transverse sectional view substantially on the line 22 of Fig. 1.

Figs. 3 and 4 are detailed sectional views showing the throttle valve in diflerent positions from that shown in Fig. 1.

Fig. 5 is a fragmentary side elevational view of the throttle valve, and

Fig. 6 is a vertical sectional view similar to Fig. 1 showing the invention embodied in a fluid pressure drill of the semi-valveless type.

The invention is shown in Figs. 1 to 5 as embodied in a fluid pressure drill of the valveless type wherein the drill cylinder 7 provides a difierential piston chamber comprising the large bore 7 a and the small bore 7 b in which reciprocates a two diameter piston 8 comprising a head 8a fitting bore 7a and a stem 8?) fitting bore 75 and arranged to impart blows to a drill stee1 9 supported in front head i 10 through an anvil block 11 supported in a guide member 12 clamped between front head 10 and cylinder 7. In order that the drill may be used for stoping work the same may be provided with the usual type of feed cylinder 13. c The admission of pressure fluid to the drill and to the feed cylinder is controlled by a throttle valve 14 which is manually operated by means of a handle 14a. Throttle valve 14 serves as a part of the fluid pressure inlet for the drill by reason of the axial bore 15 therein with which the supply pipe (not shown) connects. Valve 14 has a port 16 which in the on position of the valve communicates with the fluid pressure chamber 7 0 of the drill from which extends piston bore 7 b. Valve 14 also has a port 17 intersected by an external transverse groove 17a for supplying pressure fluid to the feed cylinder 13 and another small port 18 for a purpose presently to be described. These ports are all disposed in spaced relation axially of valve 14 which as indicated in Fig. 5 is tapered although for the sake of clearness it is not so disclosed in Figs. 1, 3 and 4.

The operation of a drill of the type shown in Fig. 1 is briefly as follows. With the piston in the position shown pressure fluid entering the drill through port 16 has immediate access to the stem end of piston 8, and also by means of passage X which registers with the reduced neck 80 of the piston to the rear face of the piston head 8a for the forward stroke, the forward end of the piston chamber being open to atmosphere through the piston controlled exhaust port Z. As the lpiston strikes its blow the rear end of large ore 7 a is vented through Z and pressure fluid is admitted to the return passage Y by the uncovering of the same by the stem of the piston to eflect the rearward stroke of the latter, the piston being forced back against the continuous high pressure in chamber 70 which is not at any time vented to atmosphere.

In the lubricating arrangement for a drill of this type which comprises the present in vention, provision is made for a lubricant If.) U

reservoir of substantial size in the walls of the cylinder 7 without increasing the external dimensions thereof, the reservoir being in the thick wall of the cylinder adjacent the small piston chamber and substantially if not wholly within a projection of the large piston chamber. One way'of making such a reservoir is to provide a series of axial bores 19 (Fig. 2) radially disposed so as to at least partly surround the small bore 7?) of the piston chamber. Bores 19 are interconnected by passages 20. A bore 21 from theexterior of the cylinder 7 provided with a plug 22 intersects one of the bores 19 andforms con venient means for filling the reservoir with lubricant. The lubricant reservoir has one or more connections to certain chambers of the drill wherein a pressure greatly above atmospheric pressure obtains when the drill is in operation. Upon the manner in which these connections are made depends the attaining of the objects of this invention. To this end passage 23 extends from the forward, or working tool, end of the reservoir to the pressure fluid chamber at the rear of the piston chamber, the quantity of fluid traversing this passage being limited by suitable means such as a plug 23a providing a restricted opening. By preference another passage 24 extends from the rearward or feed end of the reservoir, which passage terminates adjacent the throttle valve 14, a plug 24a having restricted opening being likewise provided in this passage to restrict the quantityof fluid passing therethrough. This passage 24 is adapted to register with the previously mentioned port 18 of throttle valve 14 when the latter is in a full on position as in Fig. 1. Hence passage 24 is under control of the throttle valve and is closed except when said valve is in the on or running, position shown in Fig. 1. It will accordingly be evident that the passages extending from the lubricant reservoir are arranged'to communicate with sources of fluid pressure which are not vented to atmosphere in the normal operation of the tool.

The operation of the lubricating system is as follows: When the drill is used as a stoper for driving upwardly inclined holes pressure fluid from the constant pressure chamber 70 or the piston chamber enters passage 23 and builds up pressure in the forward, or the then upper, end of the lubricant reservoir forcing lubricant therefrom through the passage 24 into the interior of throttle valve 14 where it mingles with the entering pressure fluid and is carried thereby to the working parts of the tool, When the drill is used for sinking or driving downwardly inclined holes, pressure fluid fromthe throttle valve passes through port 18 into passage 24 and builds up pressure in the rearwarththe then upper,

end of the lubricant reservoir. forcing lubrican-t from the latter out through passage 23 whence it is sprayed into the pressure fluid chamber 70 and is carried by the pressure fluid therein to the working parts of the tool.

Fig. 4 shows the position of the throttle valve when the drill in use as a. stoper is being placed in position, wherein motive fluid passes through port 17 along groove 17 a to feed cylinder 13 to move the drill bodily into engagement with the .work. Inth'is position port 18 does not register with passage 24 and there is no flow of lubricant similarly in the ofi position of the throttle valve (Fig. 3) the connection of the lubricant reservoir and the fluid inlet is broken since port 18 is not in register with passage 24. Hence the lubricating system operates in the mannerabove described only when the'throttle valve is in the on position of Fig.1.

In Fig. 6 is shown the same lubricating system operating in substantially the same manner in a drill of the semi-valveless type utilizing a two diameter piston wherein the stem of the piston 8 is not formed with a reduced neck but is of uniform diameter and an automatic valve W is utilized to control the admission of fluid to the rear face of the piston head. In this form of the invention passage 24' leads to, and is controlled by, the throttle valve 14 in identically the same manner as the form shown in Fig. 1. Passage 23 opens into a cushion chamber 7d for piston 8', which chamber is never vented to atmosphere and which is open to motive fluid admitted through port 16' when the stem of piston 8' passes forwardly of opening 16". Vhile lubricant forced from passage 23 cannot pass so directly to the working parts of the tool as in the first form of the invention due to the intermittent opening and closing of chamber 7d to the motive fluid supply, nevertheless suflicient surgingand agitating of the pressure fluid in, out of and through chamber 705 is caused by the entering and receding piston stem to effect adequate distribution of the lubricant laden pressure fluid. With the exception that passage 23 opens into a cushion chamber 7d instead of into a chamber constantly in communication with the fluid inlet (as 7c of Fig. 1) the operation of the lubricating system of Fig. 6 is substantially identical withthat of Fig. 1.

From the above it will be apparent that the utilization of the cylinder wall about the reduced end of the piston chamber for a lubricant reservoir provides space for a relatively large amount of lubricant so that the filling of the same is not required .50 frequently as with the usual form of drill with a consequent decrease in the likelihood of running the drill in a dry condition, that pro viding a reservoir of large capacity in the manner shown does not increase the size of the drill,- that the means for and manner of distributing the lubricant as shown provides for a ositive feeding of the latter and its being orne in adequate amount to all of the Working parts of the drill regardless of the angular disposition of the drill, and that the flow of lubricant ceases with the operation of the tool.

I claim as my invention:

1. A percussive tool having a cylinder of substantially uniform diameter providing a two diameter piston chamber, and lubricating means for said tool comprising a lubricant reservoir formed in the thick wall of the cylinder adjacent the reduced ortion of the piston chamber, said cylinder iaving a series of axial bores forming said reservoir.

23. A percussive tool having a cylinder of substantially uniform diameter providin a two diameter piston chamber, and lubricating means for said tool including a lubricant chamber of substantial size formed in said cylinder without increasing the size thereof, said cylinder having an arcuate series of axial bores in the thick wall thereof adjacent the reduced portion of the piston chalnber, said bores being interconnected to provide said lubricant chamber.

3. In a fluid pressure percussive tool, a cylinder, a piston reciprocable therein, a throttle valve for controlling the admission of fluid pressure to the tool, said cylinder having an axially disposed lubricant reservoir and passages extending from the opposite ends of said reservoir to portions of said tool containing pressure fluid at substantially con stant high pressure when the tool is in operation, one of said passages being under control of said throttle valve.

l. In a fluid pressure percussive tool, a cylinder, a piston reciprocable therein, a throttle valve for controlling the admission of fluid pressure to the tool, said cylinder having an axially disposed lubricant reservoir, and means including an open port connecting the forward end of said reservoir to the piston chamber and a second port under control of said valve for connecting the rearward end of said reservoir to the fluid pressure inlet.

In a fluid pressure percussive tool, a cylinder having a piston chamber, a piston reciprocable therein, a throttle valve for controlling the admission of the pressure fluid, a portion of said piston chamber being maintained under high pressure when the tool is in operation, said cylinder having an axially disposed lubricant reservoir, and means establishing restricted connection between the forward end of said reservoir and said high pressure portion of the piston chamber and between the rearward end of said reservoir and the fluid pressure inlet, said last named con nection being under control of said throttle valve.

6. In a fluid pressure percussive tool, a cylinder having a differential piston chamber, a two diameter piston reciprocable therein,

one portion of the piston chamber and one pressure area of the valve being maintained continuously under high pressure when the tool is in operation, a throttle valve for controlling the admission of pressure fluid to the tool, said cylinder having a series of radially dis osed interconnected axial bores at least part y surrounding the smaller portion of the piston chamber and forming a lubricant reservoir, a restricted connection from the forward end of one of said bores to the high pressure portion of the piston chamber, and a passage extending from the rearward end of one of said bores and terminating adjacent said throttle valve, said throttle valve having means arranged to register with said passage to establish communication of the latter with the fluid inlet when said valve is turned to the full on position.

7. A percussive tool having a cylinder of substantially uniform diameter providing a two diameter piston chamber, lubricating means for said tool comprising a lubricant reservoir formed in the thick wall of the cylinder adjacent the reduced portion of the piston chamber, said cylinder having a series of axial bores forming said reservoir, means establishing a restricted but continuously open connection between the forward end of said reservoir and a high pressure portion of the piston chamber and means establishing a restricted but continuously open connection between the rearward end of said reservoir and the motive fluid inlet.

8. A fluid pressure percussive tool having a cylinder of substantially uniform diameter providing a two diameter piston chamber, a piston reciprocable therein, a portion of said chamber being maintained under high pres sure when the tool is in operation, lubricating means for said tool comprising a lubricant reservoir of substantial size formed in said cylinder without increasing the size thereof, said cylinder having an arcuate series of interconnected axial bores in the thick wall thereof adjacent the reduced portion of the piston chamber to form said reservoir, and means establishing connection between one end of said reservoir and said high pressure portion of the piston chamber and between the other end of said reservoir and the fluid pressure inlet to produce a substantially balanced pressure on the lubricant, said connecting means being so arranged as to permit movement of the lubricant from said reservoir by gravity in a plurality of posi tions of said tool.

9. A percussive tool having a cylinder providing a two diameter piston chamber, the reduced portion of said chamber extending toward the control end of the tool, and lubrieating means for said tool comprising a lubricant reservoir of considerable capacity hollowed out of the thick wall of said cylinder adjacent said reduced portion of the piston chamber, said reservoir being within the axial limits of the small piston chamber and within or substantially within a projection of'the large piston chamber so as to avoid infi creasing the size'of the tool. I

'10. A percussive tool having a cylinder of substantially uniform external diameter throughout its length and providing a two diameter piston chamber with its large di-. 7

ameter portion in the forward end thereof, and means utilizing the thick Wall of the cylinder adjacent the reduced portion of the piston chamber and within the axial limits of said reduced portion to provide a lubrii? cant chamber of large capacity.

11. A percussive tool having a cylinder of substantially uniform external diameter throughout its length and providing'a two diameter piston chamber with its small di- 2 ameter portion adjacent the motive fluid inlet end of the tool, means utilizing the thick wall of said cylinder adjacent'the reduced portion of the piston chamber and within the axial limits of said reduced portion to pro- 35 vide a lubricant reservoir of large capacity,

and lubricant passages connecting with axially spaced portions of said reservoir to provide for movement of lubricant therefrom in all working positions of said tool.

59 12. A percussive tool having a cylinder of substantially uniform external diameter throughout its length and providing a two diameter piston chamber with its small diameter portion adjacent the motive fluid inlet end 1; 35 of the tool, means utilizing the thick wall of said cylinder adjacent the reduced portion of the piston chamber and within the axial limits of said reduced portion to provide a lubricant reservoir of large capacity, and lubrifl. cant passages connecting with axially spaced portions of said reservoir to provide for movement of lubricant therefrom in all working positions of said tool, one of said passages leading into said motive fluid inlet 45 and the other passage into the piston chamr. Signed by me at Detroit, Mich., this 29th day of January 1925. V

ERNEST PENBEBTHY. 

